/*
 * yauosk - Yet Another Useless Operating System Kernel
 *
 * Copyright (c) 2009-2010 Matteo Cicuttin
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 * derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
#define SEG_ACCESSED    0x01

/* Readable is for executable segments, writeable for non-executable */
#define SEG_R           0x02
#define SEG_W           0x02

/* Conforming for executable segments, Grow Down for data segments*/
#define SEG_C           0x04
#define SEG_GD          0x04

#define SEG_X           0x08

#define SEG_RING_0      0x00
#define SEG_RING_1      0x20
#define SEG_RING_2      0x40
#define SEG_RING_3      0x60

#define SEG_P           0x80

#define SEGDESC(base, limit, access, flags) \
    .word (((limit) >> 12 ) & 0xffff); \
    .word ((base) & 0xffff); \
    .byte (((base) >> 16) & 0xff); \
    .byte (access | 0x10); \
    .byte ((((limit) >> 28) & 0x0f) | ((flags << 4) & 0xf0)); \
    .byte (((base) >> 24) & 0xff)
    
